This invention relates to a saw chain grinding machine.
As is well known, saw chains in popular use have right and left cutter elements on alternate cutter links. Two common types of chains are the "chipper" or "round tooth" chain and the "chisel bit" chain. The cutter elements of the chipper chain have a somewhat simplified shape comprising a curved, hooked-shaped edge. In sharpening this chipper chain, a properly shaped grinding wheel is inclined downwardly and obliquely relative to the cutter element with the grinding wheel being laterally parallel with the cutter element. The cutter elements of the chisel bit chain have generally L-shaped surfaces with angles meeting at a sharp corner. This latter type of cutter element is more complicated in its grind since the surfaces thereof meet at precise and predetermined angles. In sharpening this latter chain, the grinding wheel is also inclined downwardly into the cutter element and the engagement is also from the front at an oblique angle. However, in order to achieve the proper grind on the angular edges, the cutter element must have a tilted relation to the grinding wheel.
Structure to achieve a highly efficient grinding of the chisel bit chain is shown in my U.S. Pat. No. 4,836,058. In this structure, a pivotal support of the chain holder is provided whereby the cutter element being sharpened is held on the pivotal axis of the holder, namely, the pivotal axis of the chain holder passes through the area of the grinding engagement and all the cutter elements, right and left, use the same radial grinding point on the edge of the grinding wheel. To accomplish this feature, the support of the chain holder is parallel with the plane of the grinding wheel and the support of the chain on the holder is at an angular plane relative to the grinding wheel, whereby the proper grind of both right and left cutter elements is accomplished by pivoting the holder between identical opposite angular positions.